Gpio connection to pi and reed relay


Currerntly building a food computer.

I have the GPIO ribbon cable that connects to the PI. What pins do we connect it to? The cable isn’t the same length as the pins on the PI and it seems to push a row of pins aside as you plug it in? is this the case?

Also in the written instructions in section 9 pertaining to the Controller Module it refers to a reed relay plugged into pin 22 on the Arduino. I don’t see it in the bill of materials and it doesn’t seem to be referenced anywhere else. What is it?